Sewing machine gear-lubricating system



July 30, 1940. R. KAIER SEWING MACHINE GEAR-LUBRICATING SYSTEM Filld June 25, 1937 2 Sheets-Sheet l Righard Wanna July 30, 1940. KAlER 2,209,336

SEWING MACHINE GEAR-LUBRICATING SYSTEM Filed June 25, 1937 2 Sheets-Sheet. 2

l V 1 36 3.5 fi

I LL31? I j 1 E. L 0

Patented July 30, 1940 UNlTED STATES PATENT OFFICE Richard Kaier, Craniord, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J.', a corporation of New Jersey Application June 25, 1937, Serial No. 150,224

5 Claims.

This invention relates to sewing machines having gear-connected rotary shafts. A machine of the type in question is disclosed, for example, in United States patent of Philip Diehl, Re. 16,119, reissued July 21, 1925. In this machine the top and bottom pairs of gears are lubricated by a semi-fluid lubricant, as grease or Vaseline, contained in two separate gear-cases. Such a machine, when commercially used at speeds above 4000 stitches per minute suffers from rapid deterioration and destruction of the gears, particularly the top gears, and much time and effort has been expended in unsuccessful attempts to overcome the difficulty.

After having thoroughly canvassed the various possibilities of gear failure, such as shaft whip, improper tooth-shape, etc., it has finally been discovered that lack of adequate lubrication is the chief cause of gear-failure at high operating speeds.

The present invention has for an object to provide a simple and practical system for adequately lubricating the gears of a high-speed sewing machine so that the machine can be commercially operated at speeds which have heretofore caused premature destruction of the gears.

A further object of the invention is to provide a gear-lubricating system which is economical of lubricant and cool-running, and which only requires the occasional attention of an operator to maintain it in efficient operative condition.

Still further, the invention has for an object to provide a gear-lubricating system which is practically leak-proof and is applicable to a sewing machine of conventional design.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts. hereinafter set forth and illustrated in the accompanying drawings of apreferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Fig. 1 is a side elevation, partly in section, of a sewing machine embodying the invention. Fig. 2 is a section on the line 22, Fig. 1. Fig. 3 is a section on the line 3-3, Fig. 1. Figs. 4 and 5 are, respectively, disassembled perspective views of the bottom and top gear-cases shown in Figs. 1, 2 and 3. Fig. 6 is a top plan view of the top bearing bushing for the vertical shaft of the machine, and Figs. '1 and 8 are sections on the lines 1-1 and 8-8, respectively, Fig. 1.

Referring to the drawings, represents the bed of the sewing machine frame upon which stands the upright member or standard 2 of the gooseneck 3 terminating in the head 4 which carries the usual reciprocatory needle-bar 5, needle 6, presser-foot 1, take-up B and tension-de 5 vice 9.

Journaled in the gooseneck 3, in the end ballbearings l0, H and intermediate bearing I2 is the upper horizontal rotary main shaft l3 which at its forward end is connected in the usual man- 10 ner to drive the needle-bar 5 and'take-up 8. This shaft carries the usual feed-lift eccentric l4 and feed-advance eccentric l5 which drive the usual four-motion feed-dog (not shown).

Journaled below the bed I, in the cylindrical 1 bearing bushings l6, i1 is the lower rotary shaft 18 which carries the usual rotary hook device l9 complemental-to the needle 6 in the formation of stitches.

J ournaled in the standard 2, in the cylindrical 2o bearing bushings 20, 2|, is the upright tubular shaft 23 which is formed externally at its lower end with a spiral oil-pumping groove 24 working in the pump-cylinder 25 fixed in the pump-well 26 in the bottom section 21 of the horizontally 25 split lower gear-casing. The upper. section 28 of the lower gear-casing has an aperture 23 which snugly fits over the lower end of the bearing bushing 2|. The separable sections 21, 28 part at a plane containing the axis of the shaft 18 and 30 normal to the axis of the shaft 23. This provides for a lubricant well below the parting plane and minimizes the risk of leakage. The sections 21, 28 may be elongated transversely of the machine bed and are formed with the matched 35 semi-circular openings 30 which are clamped upon the rearward end of the bearing bushing H by the fastening screws 30 which secure the gear-case sections together.

The lower gear-case section 21 may be formed with a steadying foot 3| which is secured by a screw 32 to the sewing machine frame leg 33. The rearwardly extending portion of the lower section 21 is also formed at the parting plane between the sections 21, 28, with an integral oilretaining roof or top-wall 34, to prevent possible leakage of oil through a crack at the parting plane when the sewing machine is canted for the usual inspection of the underbed mechanism. The upper section 28 of the lower gear-case is formed with an aperture 35 entered by the tube 36 extending downwardly through the machine bed I. A gauge stick may be inserted in the tube 36 to test the level 0-0 of oil in the sump of the lower gear-case. The lower gear-case 21, 28 u encloses the lower pair of bevel gears 31, 3| fixed to the shafts l8 and 23, respectively.

The upper pair of gears 3|, 44 are fixed. respectively, to the main shaft, i3 and upri ht shaft 23. These gears are enclosed by the horizontally split upper gear-casing, the sections 4|, 42 of which are secured together by screws 43 accessible through the specially provided screw-driver holes 43 in the gooseneck.

The upper gear-case sections .4l, 42 are clamped together upon and grip the reduced end 44 of the frame bushing 45. They also closely but freely embrace the cylindrical hub of the gear 39. The lower section 42 of the upper gear case has a circular or tubular downwardly extending portion 46 which is received in the flanged head 41 of the bushing 20.

The bushings 20, 2| are formed with longitudinally extending oil-return ducts 48 alongside and in communication with the bear ings for the upright shaft 23, so that such shaft bearings will be thoroughly lubricated by the return stream of oil. The bushings 20 and 2| are connected together by the tube 48 which is concentric with the upright shaft 23.

When the machine is in operation, the rotation of the spirally grooved upright shaft 23 forces the fluid oil in the sump downwardly in the pump-cylinder 25 to the pressure chamber 50 from which the oil flows upwardly through the hollow upright shaft 23 and out of the upper end of such shaft within the circle of teeth of the bevel gear 40. As the oil emerges from the upper end of'the shaft 23 it is thrown by centrifugal force radially outwardly of the gear body 40, as a sheet of oil, simultaneously in all directions in the plane thereof, and floods the teeth of such gear, as well as the meshing teeth of the companion gear 39 at the instant of contact, so that the oil is applied where it is needed before it is thrown oif of the teeth by centrifugal force.

The oil, after flooding the teeth of the gears runs down through the outlet 46 into the flanged head 41 of the bearing bushing 20 and through the oil-return duct 48 therein to the tube 49 through which it flows to and through the duct 48 in the bushing 2| and into the lower gear-case 21, 28. Return oil from the lower duct 48 floods the lower gears 31, 38 sufliciently to prevent permature destruction thereof. These lower gears are not subjected to the destructive wear to which the upper pair of gears are subjected and hence do not require to be radially flooded. There is an oil mist created by agitation of oil by the gears in the lower gear-case which is also helpful in lubricating the lower gears.

The gear-cases are preferably die-cast from any suitable material and the lower gear-case is preferably elongated crosswise of the machinebed to increase its oil-capacity.

The .invention is not to be understood as limited to the details of construction and relative arrangements of parts shown and described, as various modifications may be readily made, by those skilled in the art, within the spirit and scope of the invention.

Having thus set forth the nature of the invention what I claim herein is:

1. A sewing machine having a frame including a bed and a gooseneck, lower and upper rotary shafts journaled in said bed and gooseneck, an

upright shaft having an external spiral oilpumping groove at its lower end and an internal oil-delivery duct in communication with said groove and leadingtoahd through the upper end of said upright shaft, lower and upper gear-connections between said upright shaft and said lower and upper shafts, lower and upper gearhousings separate from said frame and enclosing said gear-connections, a pump-cylinder emright shaft within said lower gear-housing, and an oil-return connection from the upper to'the lower gear-housing.

2. A sewing machine having a frame including bracing the spirally grooved portion of said up- 10 a bed and a gooseneck, lower and upper rotary 15 shafts journaled in said bed and gooseneck, vertically alined bearing bushings mounted in said gooseneck and formed internally'with oil-return ducts, a hollow upright shaft journaled in said bushings, tween said upright shaft and said lower and upper shafts, lower and upper gear-housings separate from said frame and enclosing said gearconnections, means in said lower gear-housing to pump oil upwardly through said shaft to the gears in said upper gear-housing, and return means to conduct oil from the upper gear-housing downwardly through said vertically ing.

3. The combination with three shafts, two pairs of bevel gears interconnecting said shafts, and two substantially oil-tight split gear-housings detachably enclosing said pairs of bevel gears, of an oil-pump driven by one of said shafts in one of said gear-housings, means to conduct oil from said pump to the other gear-housing, and oil-return means leading from. the other gear-housing to the gear-housing containing the oil-pump.

4. A sewing machine having a frame including a bed and a gooseneck, lower and upper rotary shafts journaled in said bed and gooseneck, an upright shaft, lower and upper gear-connections between said upright shaft and said lower and upper shafts, lower and upper gear-housings separate from said frame and enclosing said gearconnections, and means to circulate oil to-and-' fro between said gear-housings, said lower gearhousing being split horizontally into two detachably connected sections elongated transversely of the machine bed, the rearwardly disposed portion of the lower section having an integrally formed roof-portion at the parting plane between said sections.

5. In a sewing machine, the combination with two horizontal parallel shafts, an open-ended tubular vertical interconnecting shaft at right angles thereto, and two pairs of bevel gears connecting said shafts, of two substantially oil-tight split gear-[housings detachably enclosing said pairs of bevel gears, the lower one of said gearhousings being formed in its bottom wall with a downwardly projecting closed bottomed pumpcylinder,.the lower end-portion of said tubular shaft being externally spirally grooved and projecting into said pump-cylinder but terminating short of the lower closed end of the latter, and an oil-return duct leading from the upper to the lower gear-housing.

RICHARD KAIER.

lower and upper gear-connections be- 20 hollow upright 25 alined bearing bushings to the lower gear-housso 

